JN0-106 Routing Fundamentals Practice Question
A router has two ISIS adjacencies to the same router, both with equal metrics. The router installs both routes in the routing table and performs load balancing. The network team wants to verify that both next-hops are being used for a particular destination. Which command provides this information?
⚠ Common exam trap
Watch out — candidates often assume `show route` commands (like `detail` or `extensive`) confirm actual forwarding behavior, but in Junos, only the forwarding table reveals which next-hops are truly used for packet forwarding, especially under ECMP.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
`show route forwarding-table destination 10.0.0.0/24`
The `show route forwarding-table destination 10.0.0.0/24` command displays the actual forwarding entries in the Packet Forwarding Engine (PFE), including all next-hops used for load balancing. Unlike the routing table, the forwarding table shows which next-hops are actively installed and used for forwarding traffic, making it the definitive command to verify equal-cost multipath (ECMP) usage.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
`show route 10.0.0.0/24 extensive`
Why it's wrong here
`show route 10.0.0.0/24 extensive` dumps the full routing-table entry for that prefix, including every IS-IS next-hop, preference, and metric. However, it only shows the protocol-level next-hops that the routing daemon computed; it does not reveal the forwarding table's resolved next-hop list or which next-hop is actually programmed into the Packet Forwarding Engine. For an ECMP pair, the extensive output may list both next-hops, but it cannot tell you whether both are installed in hardware or how the flow hash distributes traffic—so it cannot confirm what is really used for forwarding.
- ✓
`show route forwarding-table destination 10.0.0.0/24`
Why this is correct
`show route forwarding-table destination 10.0.0.0/24` is the authoritative command for verifying actual forwarding behavior. It displays the forwarding-table entry, where the next-hop has been resolved to a specific interface and IP address (e.g., via ARP or neighbor discovery), and it explicitly shows whether multiple next-hops are installed with equal weights for load balancing. This is the only command in the set that shows the PFE's forwarding state, so it directly answers which next-hops are used when forwarding packets to 10.0.0.0/24.
- ✗
`show route protocol isis`
Why it's wrong here
`show route protocol isis` lists every route that IS-IS has installed in the routing table, without any destination-specific filter. To find 10.0.0.0/24 you would need to scroll through the output or apply an additional filter, and even then the output only presents routing-table next-hops and IS-IS attributes—it never shows the forwarding table or hardware adjacency entries. This command is too broad and stays in the control plane, so it cannot reveal which next-hop the forwarding engine actually uses for that prefix.
- ✗
`show route 10.0.0.0/24 detail`
Why it's wrong here
`show route 10.0.0.0/24 detail` gives a rich routing-table view: next-hop addresses, protocol flags, area information, and route preference. But like the extensive variant, it remains a control-plane snapshot: the next-hops shown are the logical IS-IS next-hops, not necessarily the resolved forwarding next-hops with interfaces and weights. The detail output might list two ECMP next-hops, but it does not show whether those next-hops are actually installed in the forwarding table or how load balancing is performed at line rate.
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About these practice questions
Courseiva writes every JN0-106 question from scratch — 156 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
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Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This JN0-106 practice question is part of Courseiva's free Juniper Networks certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the JN0-106 exam.